Core Shell Particle Synthesis with Oxygen Ratio Control

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Solution Overview

Problem

The synthesis of core shell particles with high luminous efficacy and narrow emission half-width is challenging due to fluctuations in synthesis conditions, leading to variations in composition and particle size, which affect emission characteristics.

Innovation Solution

A core shell particle structure is developed with a core containing a Group III element and a Group V element, surrounded by multiple shell layers, where the molar ratio of oxygen to the Group III element is controlled to 6.1 or less, using specific synthesis steps and atmospheres to minimize surface oxidation and defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional synthesis methods are used to produce core shell particles, then production can be achieved with standard procedures, but luminous efficacy fluctuates and emission half-width becomes wide due to variations in synthesis conditions

Engineering Contradiction:
Improveluminous efficacyVSAvoidemission half-width
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by precisely controlling the molar ratio of oxygen to Group III element (keeping it at 6.1 or less) and controlling particle size within specific ranges (2-50 nm). By adjusting these parameters during synthesis, the method achieves high luminous efficacy and narrow emission half-width, resolving the contradiction between reliability and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements local quality by creating a core-shell structure where the core contains Group III-V semiconductor materials with specific composition, and the shell provides protective and functional properties. This localized differentiation of material properties within the particle structure enables high luminous efficacy while maintaining precise emission characteristics.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If synthesis conditions are varied to explore different compositions, then material diversity is achieved, but particle size uniformity decreases leading to broader emission spectra

Engineering Contradiction:
Improvecomposition controlVSAvoidparticle size uniformity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent uses parameter changes to control particle size within the specific range of 2-50 nm while maintaining composition flexibility. By establishing clear parameter boundaries (oxygen/Group III molar ratio ≤ 6.1, particle size 2-50 nm), the method achieves both adaptability in composition and precision in particle size uniformity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary action by pre-establishing optimal synthesis conditions and parameter ranges before actual particle production. By determining the appropriate oxygen to Group III element ratio and particle size range in advance, the method ensures both compositional versatility and size uniformity are achieved systematically.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If surface oxidation is allowed to occur during synthesis, then synthesis process is simpler, but surface defects increase reducing luminous efficacy

Engineering Contradiction:
Improvesynthesis process simplicityVSAvoidluminous efficacy
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies inert atmosphere by controlling the synthesis environment to prevent surface oxidation of the core shell particles. By maintaining an inert or controlled atmosphere during synthesis, the method avoids surface defects that would reduce luminous efficacy, while still keeping the process relatively simple through atmospheric control rather than complex surface treatment steps.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent converts the potential harm of oxidation into a benefit by precisely controlling the oxygen to Group III element molar ratio to be 6.1 or less. This controlled oxygen presence prevents excessive oxidation and surface defects, transforming what could be a harmful factor into a controllable parameter that enhances luminous efficacy.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach results in core shell particles with enhanced luminous efficacy and narrowed emission half-width, achieved through controlled synthesis conditions that suppress surface oxidation and defect formation, leading to uniform particle size and improved emission characteristics.

Implementation Method 1

a coordination molecule in at least a part of an outermost surface

Methodology Applied
Scientific EffectCoordination bonding: Chemical Bonding

Implementation Method 2

at least oxygen is detected by X-ray photoelectron spectroscopy analysis, and a molar ratio of the oxygen to the Group III element contained in the core, which is acquired by X-ray photoelectron spectroscopy analysis

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS10465111B2Core shell particle, method of producing core shell particle, and film
Publication Date: 2019.11.05 FUJIFILM CORP

AI summary

An object of the present invention is to provide a core shell particle having high luminous efficacy and a narrow emission half-width; a method of producing the same; and a film formed of the core shell particle. The core shell particle of the present invention includes: a core which contains a Group III element and a Group V element; a first shell which covers at least a part of a surface of the core; a second shell which covers at least a part of the first shell; and a coordination molecule in at least a part of an outermost surface, in which at least oxygen is detected by X-ray photoelectron spectroscopy analysis, and a molar ratio of the oxygen to the Group III element contained in the core, which is acquired by X-ray photoelectron spectroscopy analysis, is 6.1 or less.